Working with column types

This typeclass defines and maps to haskell types that Cassandra
natively knows about and uses in sorting and potentially validating
column key values.

All column keys are eventually sent to and received from Cassandra
in binary form. This typeclass allows us to map some Haskell type
definitions to their binary representation. The correct binary
serialization is handled for you behind the scenes.

For simplest cases, just use one of the string-like instances, e.g.
ByteString, String or Text. Please keep in mind that these
are just mapped to untyped BytesType.

Remember that for special column types, such as TLong, to have
any effect, your ColumnFamily must have been created with that
comparator or validator. Otherwise you're just encoding/decoding
integer values without any Cassandra support for sorting or
correctness.